It is known to provide an inflator for inflating an inflatable vehicle occupant protection device, such as an air bag. One particular type of inflator is a hybrid inflator, which incorporates and combines elements of both stored gas inflators and solid propellant gas generators.
Hybrid inflators can be generally elongated and tubular in form, including a reaction chamber that contains the solid propellant, and a pressure chamber that contains the stored gas. The reaction and pressure chambers can be separated by a rupturable membrane, such as a burst disk. An igniter assembly is supported at the end of the inflator adjacent the reaction chamber, and is typically isolated from the reaction chamber by a rupturable membrane, such as a burst disk. A diffuser assembly is supported at the end of the inflator adjacent the pressure chamber. The pressure chamber and the diffuser assembly are separated from one another by a rupturable membrane, such as a burst disk.
Upon actuation of the inflator, the pyrotechnic material of the igniter ignites and the burst disk is ruptured in response. Reaction products from the igniter enter the reaction chamber and ignite solid propellant, causing a reaction that produces reaction products (e.g., heat and inflation fluid). The burst disk separating the reaction chamber and the pressure chamber ruptures in response to the reaction of the solid propellant. The reaction products from the solid propellant enter the pressure chamber and mix with the stored gas. The added heat and inflation fluid increases both the amount of fluid and the fluid pressure in the pressure chamber. The burst disk separating the diffuser from the pressure chamber ruptures. The inflation fluid is directed out of the inflator through the diffuser and into the protection device.